“What if the placebo group is not used and you just measure results and determine efficacy compared to the specific cancer patients at large where the standard of care efficacy is already known?”
Then you have an unblinded uncontrolled non-randomised “study” which is literally worthless.
And I really really didn’t “make your point for you” because your claim that there is no placebo effect is both wrong and completely contradicted by actual evidence .
Both the placebo effect and the Hawthorn effect with which you have rather bafflingly confused it are of course real.
"Nobody ever went broke underestimating the intelligence of the American public."
H. L. Mencken
"It’s easier to fool people than to convince them that they have been fooled."